1. Field of the Invention
This invention relates to a recording and/or reproducing apparatus employing a disc such as a magneto-optical disc or an optical disc as a recording medium for information signals. More particularly, it relates to such apparatus in which its recording and/or reproducing unit is supported within a main body of the apparatus in a floating state via a plurality of damper units and elastic members.
2. Description of the Related Art
Up to now, a recording and/or reproducing apparatus employing a recording medium such as a magneto-optical disc or an optical disc for information signals has been proposed. The magneto-optical disc or the optical disc, employed as a recording medium for such recording and/or reproducing apparatus, is contained in a main cartridge body to form a disc cartridge and loaded in such state in the recording and/or reproducing apparatus.
The recording and/or reproducing apparatus has an optical pickup and a magnetic head as means for writing and/or reading information signals on or from the magnetic recording medium. The optical pickup and the magnetic head are mounted on a chassis provided in the main body of the apparatus to constitute a recording and/or reproducing unit. On the other hand, the disc cartridge having the magneto-optical disc or the optical disc therein as a recording medium is loaded at a cartridge loading position in the recording and/or reproducing apparatus so as to be positioned relative to the recording and/or reproducing unit provided in the recording and/or reproducing apparatus. When the disc cartridge is loaded in the cartridge loading position, information signals are recorded on the magneto-optical disc with the aid of the optical pickup and a magnetic head, or the information signals recorded on the magneto-optical disc or the optical disc are reproduced.
It is noted that, if impacts are applied to the main body of the apparatus to produce vibrations in the recording and/or reproducing unit, it becomes impossible to record or reproduce information signals on or from the recording medium. That is, if the recording and/or reproducing unit is subjected to vibrations, the optical pickup is deviated in its position relative to the recording medium, such that it becomes impossible for the light beam radiated by the optical pickup to follow the recording track formed on the recording medium, thus rendering it impossible to record/reproduce information signals. Above all, when writing information signals on the magneto-optical disc, the information signals and table-of-contents data concerning the information signals are written in this order. The table-of-contents information indicates addresses or the like (which are the write positions of the information signals recorded on the magneto-optical disc) and represents the information indispensable in reading out the recorded information. The information signals, for which associated table-of-contents information has not been recorded, cannot be subsequently read out. Consequently, should track skip of the light beam scanning a recording track deviated from the pre-set recording track due to vibrations be produced in the course of recording of the information signals, or when the recording of the information signals has been completed but the recording of the associated table-of-contents information has not been completed, it becomes impossible to read out the recorded information signals.
With certain versions of this type of the recording and/or reproducing apparatus, especially of the portable type, the recording and/or reproducing unit is supported in a floating state in the main body of the apparatus via a plurality of damper units. Such a damper unit is made up of an elastic tubular section formed of a visco-elastic material, such as rubber, as a vibration absorbent member, fitted on a pivot set on a frame of the main body of the apparatus, and a compression coil spring, as an elastic member, fitted on the outer side of the elastic tubular member. On this elastic tubular section of the damper unit is supported a supporting piece formed on a chassis constituting the recording and/or reproducing unit mounting the optical pickup. Thus the recording and/or reproducing unit is supported in a floating manner on the frame constituting the main body of the apparatus by means of the damper units.
With the recording and/or reproducing unit thus supported on the main body of the apparatus by means of the damper units, any impacts or vibrations applied to the main body of the apparatus may be absorbed by the damper units, so that information signals may be recorded and/or reproduced without being affected by the impacts or vibrations.
Meanwhile, the damper unit supporting the recording and/or reproducing unit has not only the function for absorbing impacts or vibrations applied to the main body of the apparatus, but also the function of supporting the recording and/or reproducing unit with respect to the main body of the apparatus. Thus it is necessary for the damper unit to exhibit resiliency high enough to support the recording and/or reproducing unit, such that it is difficult to lower the resonant frequency of the damper unit and thus the vibrations cannot be absorbed sufficiently. In addition, the elastic tubular member constituting the damper unit is put under a large weight of the recording and/or reproducing unit and hence in a state of being perpetually elastically deformed, while it is elastically deformed on application of vibrations under the weight of the recording and/or reproducing unit, so that it is deformed beyond the elastic limit. Thus the elastic tubular section is susceptible to creepage and formation of crevices, such that sufficient durability cannot be maintained. Besides, the recording and/or reproducing unit, supported by the above-described damper unit, cannot be maintained at the correct supporting position relative to the main body of the apparatus due to chronological changes of the elastic tubular section, thus leading to deviation in the relative supporting position of the recording/reproducing unit with respect to the main body of the apparatus. For example, there is produced a deviation between the holder for the disc cartridge provided on the main body of the apparatus and the cartridge loading position on the reproducing unit, thus occasionally rendering it impossible to load the disc cartridge in position.
On the other hand, the damper units, supporting the recording and/or reproducing unit in a floating manner relative to the main body of the apparatus, are elastically deformed on application of impacts or vibrations to the main body of the apparatus, for absorbing the impacts or vibrations. If the damper units are elastically deformed, the recording and/or reproducing unit, supported by these damper units, is shifted or deviated relative to a frame constituting the main body of the apparatus. If the damper units, thus elastically deformed under impacts or vibrations applied to the main body of the apparatus, are collided against the frame of the recording and/or reproducing unit, the impacts or vibrations applied to the main body of the apparatus are directly transmitted to the recording and/or reproducing unit. Thus it becomes impossible for the light beam to follow the recording track formed on the recording medium and hence to record and/or reproduce information signals with optimum recording/reproducing characteristics.
In the recording and/or reproducing apparatus in which the recording and/or reproducing unit is supported in a floating manner with respect to the main body of the apparatus, there is provided a gap between the recording and/or reproducing unit and the frame which is large enough to permit the damper units to be moved without being collided against the recording and/or reproducing unit when the damper units undergo elastic deformation. By provision of such gap between the main body of the apparatus and the recording and/or reproducing unit, it becomes difficult to achieve size reduction of the recording and/or reproducing apparatus.